Diol (meth) acrylate compound having urethane bond, method for producing the same, and polymer thereof

ABSTRACT

The present invention provides compounds having in their molecule a structure contributing to high hydrophilicity, and having high photopolymerizability, as well as polymers of such compounds, and a method for producing the compound. The compounds are diol (meth)acrylate having a urethane bond represented by the formula (1), and cyclic ketal (meth)acrylate having a urethane bond represented by the formula (2): 
                         
(R 1 : H, —CH 3 ; R 2 : —(CH 2 )n-; R 3 : —(CH 2 )m-; n: 1-4; m: 1-8; (AO): C2-C4 oxyalkylene group; x: 0-1000; R 4 , R 5 : H, —CH 3 , —C 2 H 5 ).

CROSS REFERENCE TO PRIOR APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/259,543, filed Oct. 25, 2005, now U.S. Pat. No. 7,557,239.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a novel diol (meth)acrylate compoundhaving a urethane bond that is widely useful in the fields of coatings,adhesives, shapable materials, inks, printing materials, electricalinsulating materials, optical materials, dental materials, medicalmaterials, or the like, as well as a polymer of the compound and amethod for producing the compound. The present invention also relates toa cyclic ketal (meth)acrylate compound having a urethane bond and apolymer thereof that find one of their applications as a startingmaterial for the manufacture of the above-mentioned diol (meth)acrylatecompound having a urethane bond and a polymer thereof.

2. Description of Related Art

(Meth)acrylate monomers, which are known to have high reactivity, areused alone or in copolymerization with another ethylenic unsaturatedcompound, for producing polymer compounds that are highly versatile andcapable of meeting various demands, with the aid of heat, UV rays,electron beams, or radical polymerization initiators. Such(meth)acrylate monomers are used not only in the fields of adhesives andcoatings, for example, but also have recently come to be used in thefields of electronic and dental materials. In the field of medicalmaterials, in particular, hydrophilic (meth)acrylate compounds, such ashydroxyethylmethacrylate, glycerol methacrylate, and vinylpyrrolidone,have been proposed and are already in practical use.

As the (meth)acrylate monomers have come to be used in the fields ofelectronic and dental materials, which require high purity andperformance for the materials, the monomers are now desired to meet newdemands, including excellent affinity to non-aqueous materials,adhesivity, and hydrophilicity, as well as functionality such asphotopolymerizability.

Examples of (meth)acrylate monomers that could meet such demands includea phosphorous-containing urethane (meth)acrylate compound as proposed inJP-2003-212954-A, and a photosensitive composition containingpolyfunctional urethane acrylate having a (meth)acryloyl group proposedas a color filter material in JP-2003-315998-A.

However, there still remain problems in polymerizability of the monomersor the composition, adhesivity to a substrate when used in a resist, andeasiness of synthesis, which problems have not been solved sufficiently.Therefore, development of novel (meth)acrylate monomers is eagerlydemanded that are excellent in photopolymerizability, adhesivity, andeasiness of manufacture.

BRIEF SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a diol(meth)acrylate compound having a urethane bond that has in its moleculea structure contributing to high hydrophilicity and has highphotopolymerizability, as well as a polymer of such a compound.

It is another object of the present invention to provide a method foreasily producing the above diol (meth)acrylate compound having aurethane bond.

It is yet another object of the present invention to provide a cyclicketal (meth)acrylate compound having a urethane bond and a polymerthereof that may find one of their applications as a starting materialfor the above diol (meth)acrylate compound having a urethane bond and apolymer thereof.

The present inventors have made intensive researches for achieving theabove objects, to find out that a diol (meth)acrylate compound having aurethane bond which has in its molecule a hydrophilic (meth)acrylategroup, a hydrophilic urethane bond, and a plurality of hydroxyl groups,is the monomer that could achieve the above objects, thereby completingthe present invention.

According to the present invention, there is provided a diol(meth)acrylate compound having a urethane bond represented by theformula (1) (abbreviated as compound (1) hereinbelow):

wherein R₁ stands for a hydrogen atom or a methyl group, R₂ stands for—(CH₂)n-, and R₃ stands for —(CH₂)m-, provided that n is an integer of 1to 4 and m is an integer of 1 to 8; (AO) stands for an oxyalkylene grouphaving 2 to 4 carbon atoms, and x is an integer of 0 to 1000.

According to the present invention, there is also provided a cyclicketal (meth)acrylate compound having a urethane bond represented by theformula (2) (abbreviated as compound (2) hereinbelow):

wherein R₁ to R₃, (AO), and x are the same as those in the formula (1);R₄ and R₅ may either be the same or different, and each stands for ahydrogen atom, a methyl group, or an ethyl group.

According to the present invention, there is further provided a methodfor preparing compound (1) comprising the steps of:

(a) subjecting a cyclic ketal represented by the formula (3) and a(meth)acryloyloxyalkyl isocyanate represented by the formula (4) tourethane reaction to obtain compound (2):

wherein R₁ to R₅, (AO), and x are the same as those in the formulae (1)and (2), and

(b) subjecting compound (2) to hydrolytic ring-opening in awater-containing solvent in the presence of a catalyst.

According to the present invention, there are further provided polymersobtained by polymerizing a polymerizable material comprising compound(1) (sometimes referred to as polymerizable material (1) hereinbelow) ora polymerizable material comprising compound (2) (sometimes referred toas polymerizable material (2) hereinbelow).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing the photopolymerizability ofglyceryl-1-methacryloyloxyethyl urethane and glyceryl-1-methacrylate.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be explained in detail.

Compound (1) according to the present invention is a diol (meth)acrylatecompound having a urethane bond represented by the formula (1). Compound(2) according to the present invention is a cyclic ketal (meth)acrylatecompound having a urethane bond represented by the formula (2).

In the formulae (1) and (2), R₁ stands for a hydrogen atom or a methylgroup, with a hydrogen atom being preferred for higherphotopolymerizability. R₂ stands for a group represented by —(CH₂)n-,wherein n is an integer of 1 to 4. Specifically, R₂ stands for —CH₂—,—CH₂CH₂—, —CH₂CH₂CH₂—, or —CH₂CH₂CH₂CH₂—, with —CH₂CH₂— being preferredfor availability. R₃ stands for a group represented by —(CH₂)m-, whereinm is an integer of 1 to 8. R₃ may specifically be, for example, —CH₂—,—CH₂CH₂—, —CH₂CH₂CH₂—, or —CH₂CH₂CH₂CH₂—, with —CH₂— being preferred foravailability. (AO) stands for an oxyalkylene group having 2 to 4 carbonatoms, and may specifically be an oxyethylene, oxypropylene, oroxybutylene group. x is an integer of 0 to 1000, preferably 0 to 500 foreasiness of synthesis. When x is not 0, (AO)x may preferably be aresidue of oxyethylene polymer. In the formula (2), R₄ and R₅ may eitherbe the same or different, and each stands for a hydrogen atom, a methylgroup, or an ethyl group.

Examples of compound (1) may include glyceryl-1-methacryloyloxyethylurethane, 3,4-dihydroxybutyl-1-methacryloyloxyethyl urethane,5,6-dihydroxyhexyl-1-methacryloyloxyethyl urethane,glycerine-α-monopolyethylene glycol-1-methacryloyloxyethyl urethane, andglycerine-α-monopolypropylene glycol-1-methacryloyloxyethyl urethane,with glyceryl-1-methacryloyloxyethyl urethane being preferred for itssynthesizability.

Compound (2) may find one of its applications as a precursor of compound(1) in the preparation method of the present invention to be discussedlater. Specific examples of this compound may include2,3-O-isopropylideneglyceryl-1-methacryloyloxyethyl urethane,3,4-O-isopropylidenebutyl-1-methacryloyloxyethyl urethane,5,6-O-isopropylidenehexyl-1-methacryloyloxyethyl urethane,2,3-O-sec-butylideneglyceryl-1-methacryloyloxyethyl urethane,3,4-O-sec-butylidenebutyl-1-methacryloyloxyethyl urethane,5,6-O-sec-butylidenehexyl-1-methacryloyloxyethyl urethane,2,3-O-isopropylideneglycerine-α-monopolyethyleneglycol-1-methacryloyloxyethyl urethane, and2,3-O-isopropylideneglycerine-α-monopolypropyleneglycol-1-methacryloyloxyethyl urethane, with2,3-O-isopropylideneglyceryl-1-methacryloyloxyethyl urethane beingpreferred for its easiness of reaction.

Compound (1) of the present invention may be prepared, for example, bythe method of the present invention including the steps of:

-   (a) subjecting a cyclic ketal represented by the formula (3) and a    (meth)acryloyloxyalkyl isocyanate represented by the formula (4) to    urethane reaction to obtain compound (2), and-   (b) subjecting compound (2) to hydrolytic ring-opening in a    water-containing solvent in the presence of a catalyst.

In the formula (3), R₄ and R₅ may either be the same or different, andeach stands for a hydrogen atom, a methyl group, or an ethyl group, witha methyl group being preferred for easiness of removal of residualcyclic ketal after the reaction.

Examples of the cyclic ketal represented by the formula (3) may include2,3-O-isopropylideneglycerol, 3,4-O-isopropylidenebutanol,5,6-O-isopropylidenehexanol, 2,3-O-sec-butylideneglycerol,3,4-O-sec-butylidenebutanol, 5,6-O-sec-butylidenehexanol,2,3-O-isopropylideneglycerine-α-monopolyethylene glycol, and2,3-O-isopropylideneglycerine-α-monopolypropylene glycol, with2,3-O-isopropylideneglycerol being preferred for its easiness ofreaction.

Such a cyclic ketal may be obtained commercially, or synthesized bysubjecting glycerine and a carbonyl compound represented by the formula(5) to ring formation in a solvent, such as petroleum ether, benzene, ortoluene, in the presence of a catalyst, such as hydrochloric acid,sulfuric acid, or p-toluene sulfonic acid:

wherein R₄ and R₅ are the same as those in the formula (3).

Examples of the carbonyl compound represented by the formula (5) mayinclude formaldehyde, acetaldehyde, acetone, methyl ethyl ketone, and3-pentanone, with acetone being preferred for its easiness of removalafter reaction.

In the urethane reaction followed by preparation of a polymer, if thecyclic ketal represented by the formula (3) is replaced with a compoundhaving three hydroxyl groups in a molecule, for example, glycerine,which has not been subjected to ring formation, the reaction mass willbe gelated, failing to result a polymer.

Among the cyclic ketals, cyclic ketal glycerine-α-monopolyalkyleneglycol may effectively be prepared, for example, by a method proposed inJP-6-145341-A, namely, by adding alkylene oxide having 2 to 4 carbonatoms to isopropylidene glycerol.

In the formula (4) above, R₁ and R₂ are the same as those in the formula(1). Examples of the (meth)acryloyloxyalkyl isocyanate represented bythe formula (4) may include methacryloyloxyethyl isocyanate andmethacryloyloxypropyl isocyanate, with methacryloyloxyethyl isocyanatebeing preferred for its availability. The isocyanate may be obtainedcommercially, or may be synthesized from known materials by combiningknown processes.

In step (a) of the above method, the amount of the cyclic ketalrepresented by the formula (3) for the urethane reaction may preferablybe 1.1 to 3 times the amount of the (meth)acryloyloxyakyl isocyanate inmolar ratio. The urethane reaction proceeds without a catalyst, but inorder to shorten the reaction time, it is preferred to use a catalyst.

Examples of the catalyst may include tertiary amine compounds, such asN-methylmorpholine, N-ethylmorpholine, dimorpholinomethane, ethylmorpholinoacetate, N-(3-dimethylaminopropyl)morpholine,N-methylpiperidine, quinoline, 1,2-dimethylimidazole,N-methyldicyclohexylamine, triethylamine, pyridine,1,4-diazabicyclooctane, tetramethyl-1,3-butanediamine,tetramethyl-1,3-propanediamine, dimethyldiethyl-1,3-propanediamine,pentamethyldiethylenediamine, tetraethylmethanediamine,bis(2-dimethylaminoethyl)adipate, bis(2-diethylaminoethyl)adipate,dimethylcyclohexylamine, diethylcyclohexylamine,methyloctylcyclohexylamine, and methyldodecylcyclohexylamine; andtin-containing compounds, such as tin chloride, tetra-n-butyltin,tetraphenyltin, tri-n-butyltin acetate, dimethyldichlorotin,di-n-butyltin diacetate, di-n-butyldichlorotin, di-n-butyltin dilaurate,di-n-butyltin dilaurylmercaptide, bis(2-ethylhexyl)tin oxide, anddi-n-butyltin sulfide. Tertiary amine compounds are preferred sincethese compounds are safer even when they are contained in the reactionproduct as a residual catalyst.

The amount of the catalyst, when used, is usually 0.001 to 50 parts byweight, preferably 0.01 to 30 parts by weight, most preferably 0.1 to 10parts by weight, based on 100 parts by weight of (meth)acryloyloxyalkylisocyanate.

There is no problem even if the urethane reaction in step (a) isperformed without a solvent, or the reaction may alternatively beperformed in the presence of a solvent, if the solvent is not reactiveto (meth)acryloyloxyalkyl isocyanate. Examples of such a solvent mayinclude acetone, methyl ethyl ketone, acetonitrile, chloroform, carbontetrachloride, dichloromethane, benzene, toluene, hexane, and pyridine,with acetone being the most preferred for its easiness of removal afterthe reaction.

The amount of the solvent, when used, is about 0.1 to 1000 parts byweight, based on 100 parts by weight of (meth) acryloyloxyalkylisocyanate.

The temperature for the urethane reaction is usually 0 to 100° C..,preferably 25 to 80° C.., most preferably 40 to 60° C.. If the reactiontemperature is lower than 0° C.., the reaction may require a prolongedperiod of time to complete. If the reaction temperature is higher than100° C.., side reactions, such as polymerization, are likely to occur.The reaction time may vary depending on the reaction temperature, thekind and amount of a catalyst, but a preferred reaction time is usuallyabout 6 to 24 hours.

Through step (a), compound (2) as a precursor of compound (1) isobtained. Compound (2) may be used as it is without purification, orafter isolation and purification by treatments, such as drying underreduced pressure, as a material to be subjected to step (b) forobtaining compound (1), or subjected to preparation of a polymerizablematerial containing compound (2) to be discussed later.

According to the present invention, the precursor, compound (2), issubjected to hydrolytic ring-opening in a water-containing solvent inthe presence of a catalyst in step (b) to obtain the objective compound(1).

The catalyst for the hydrolytic ring-opening may preferably be, forexample, inorganic acid, such as hydrochloric, sulfuric, or phosphoricacid; or organic acid, such as p-toluene sulfonic acid, withhydrochloric acid being particularly preferred for its easiness ofremoval after the reaction. A preferred amount of the catalyst isusually 0.1 to 10.0 wt % of the overall reaction system.

Examples of the water-containing solvent used in the hydrolyticring-opening may include water alone, or a mixed solvent of water and awater-soluble solvent, such as methanol, ethanol, isopropanol,tetrahydrofuran (THF), acetonitrile, acetone, methyl ethyl ketone,dimethylformamide, dimethylsulfoxide, and dimethylacetamide. Amethanol/water mixed solvent is the most preferred for its easiness ofremoval after the reaction.

The temperature for the hydrolytic ring-opening is preferably in therange of 0 to 50° C.. If the temperature is higher than 50° C.., sidereactions, such as hydrolysis of ester or ester exchange reaction, mayoccur. If the temperature is lower than 0° C.., the moisture maydisadvantageously be solidified. The reaction time may vary depending onthe reaction temperature, the kind and amount of the catalyst, but maypreferably be about 1 to 6 hours.

With the progress of hydrolytic ring-opening, a carbonyl compound may begenerated as a by-product in the reaction system. Such a by-productcarbonyl compound is preferably removed from the reaction system bymeans of vacuum distillation or the like in order to shorten thereaction time.

Compound (1) prepared by the method of the present invention may be usedas it is without purification, or after isolation and purification bymeans of drying under reduced pressure, recrystallization, or columns,for preparing a polymerizable material to be discussed later.

The polymers of the present invention are obtained by polymerizingpolymerizable material (1) containing compound (1) or polymerizablematerial (2) containing compound (2).

The polymer obtained by polymerizing polymerizable material (1)containing compound (1) may alternatively be obtained by subjectingcompound (2), which has been obtained by polymerizing polymerizablematerial (2) containing compound (2), to hydrolytic ring-opening withacid.

The molecular weight of the polymers of the present invention is notparticularly limited, and may suitably be selected for exhibitingproperties required for each application, by adjusting thepolymerization conditions or the like factors. Usually, the presentpolymers may have a weight average molecular weight of about 5000 to1000000.

Polymerizable material (1) may be composed solely of compound (1), or inmixture with other monomers copolymerizable with compound (1).

Examples of such other monomers may include various (meth)acrylates,such as diethylaminoethyl(meth)acrylate, polyethylene glycolmono(meth)acrylate, glycerol (meth)acrylate, (meth)acryloyloxyethylphosphate, (meth)acryloyloxyethyl phosphorylcholine,methyl(meth)acrylate, glycidyl(meth)acrylate,dimethylaminoethyl(meth)acrylate, 2-hydroxyethyl(meth)acrylate, and2-methoxyethyl(meth)acrylate; various vinyl ethers, such as methyl vinylether; and various other radical polymerizable monomers, such asacrylamide, N,N′-dimethylacrylamide, (meth)acrylic acid, allyl alcohol,acrylonitrile, acrolein, vinyl acetate, sodium vinylsulfonate, styrene,chlorostyrene, vinylphenol, vinylcinnamate, vinyl chloride, vinylbromide, butadiene, vinylene carbonate, itaconic acid, itaconates,fumaric acid, fumarates, maleic acid, and maleates. Among these,2-hydroxyethylmethacrylate is preferred for its compatibility. For easypreparation of the polymer, polymerizable material (1) is preferablycomposed solely of compound (1).

The amount of the other monomers, when used, in polymerizable material(1) may arbitrarily and suitably be selected. For bringing out itsperformance, compound (1) is preferably contained in polymerizablematerial (1) in an amount of not less than 10 wt %.

Polymerizable material (1) may be subjected to polymerization in bulk,or in mixture with a solution. Examples of such a solution may includemethanol, ethanol, isopropanol, dimethylformamide, dimethylsulfoxide,dimethylacetamide, mixtures of water and such organic solvents, andvarious other polar solvents, with methanol being preferred for itschain transfer coefficient.

Polymerizable material (1) may be polymerized by radical polymerizationor photopolymerization.

Radical polymerization may be performed using a radical initiator.Examples of a radical initiator may include organic peroxides, such asbenzoyl peroxide and t-butylperoxy neodecanoate; and azo compounds, suchas 2,2′-azobisisobutyronitrile and 2,2′-azobisdimethylisobutyrate, with2,2′-azobisdimethylisobutyrate being preferred in view of theworkability and insolubilization of the resulting polymer.

The amount of the radical initiator may preferably be 0.1 to 5.0 partsby weight, based on 100 parts by weight of polymerizable material (1).The temperature and time for the polymerization may suitably be selecteddepending on the kind of the radical initiator, presence/absence or thekind of other monomers. For example, for polymerizing polymerizablematerial (1) composed solely of compound (1) using2,2′-azobisdimethylisobutyrate as a radical initiator, suitabletemperature and time for the polymerization are preferably 50 to 70° C..and about 8 to 48 hours, respectively.

The photopolymerization may be performed by irradiation with UV at awavelength of 254 nm or electron beam (EB) at an accelerating voltage of150 to 300 kV. Use of a photopolymerization initiator is optional, butpreferred in view of the reaction time.

Examples of the photopolymerization initiator may include2-hydroxy-2-methyl-1-phenyl-1-propanone and 1-hydroxy-cyclohexylphenylketone, with 2-hydroxy-2-methyl-1-phenyl-1-propanone being preferred forits solubility.

Polymerizable material (2) may be composed solely of compound (2) or inmixture with other monomers copolymerizable with compound (2).Polymerization of polymerizable material (2) composed solely of compound(2) results in a hydrophobic polymer, but this polymer may be givenhydrophilicity by subjecting the polymer to hydrolytic ring-opening. Onthe other hand, compound (2) per se has good copolymerizability withhydrophobic monomers, and thus may be used in mixture with hydrophobicmonomers, which are usually hard to be copolymerized with hydrophilicmonomers. In this case, compound (2) may act as a hydrophilizer ofpolymerizable material (2) to give a hydrophilic polymer.

Examples of the other monomers in polymerizable material (2) may includevarious (meth)acrylates, such as diethylaminoethyl(meth)acrylate,polyethylene glycol mono(meth)acrylate, glycerol(meth)acrylate,(meth)acryloyloxyethyl phosphate, (meth)acryloyloxyethylphosphorylcholine, methyl(meth)acrylate, glycidyl(meth)acrylate,dimethylaminoethyl(meth)acrylate, 2-hydroxyethyl(meth)acrylate, and2-methoxyethyl(meth)acrylate; various vinyl ethers, such as methyl vinylether; and various other radical polymerizable monomers, such asacrylamide, N,N′-dimethylacrylamide, (meth)acrylic acid, allyl alcohol,acrylonitrile, acrolein, vinyl acetate, sodium vinylsulfonate, styrene,chlorostyrene, vinylphenol, vinylcinnamate, vinyl chloride, vinylbromide, butadiene, vinylene carbonate, itaconic acid, itaconates,fumaric acid, fumarates, maleic acid, and maleates. Among these,methylmethacrylate is preferred for its compatibility. For easypreparation of the polymer, polymerizable material (2) is preferablycomposed solely of compound (2).

The amount of the other monomers, when used, in polymerizable material(2) may arbitrarily and suitably be selected. For bringing out itsperformance, compound (2) is preferably contained in polymerizablematerial (2) in an amount of not less than 10 wt %.

Polymerizable material (2) may be subjected to polymerization in bulk,or in mixture with a solution. Examples of such a solution may includebenzene, toluene, acetone, methyl ethyl ketone, chloroform,dichloromethane, and carbon tetrachloride solvents, with benzene beingpreferred for its chain transfer coefficient.

Polymerizable material (2) may be polymerized by radical polymerizationor photopolymerization.

Radical polymerization may be performed using a radical initiator.Examples of a radical initiator may include organic peroxides, such asbenzoyl peroxide and bis(4-t-butylcyclohexyl)peroxydicarbonate; and azocompounds, such as 2,2′-azobisisobutyronitrile and2,2′-azobisdimethylisobutyrate, with 2,2′-azobisdimethylisobutyratebeing preferred in view of the workability and insolubilization of theresulting polymer.

The amount of the radical initiator may preferably be 0.1 to 5.0 partsby weight, based on 100 parts by weight of polymerizable material (2).The temperature and time for the polymerization may suitably be selecteddepending on the kind of the radical initiator, presence/absence or thekind of other monomers. For example, for polymerizing polymerizablematerial (2) composed solely of compound (2) using2,2′-azobisdimethylisobutyrate as a radical initiator, suitabletemperature and time for the polymerization are preferably 50 to 70° C..and about 8 to 48 hours, respectively.

The photopolymerization may be performed by irradiation with UV at awavelength of 254 nm or electron beam (EB) at an accelerating voltage of150 to 300 kV. Use of a photopolymerization initiator is optional, butpreferred in view of the reaction time.

Examples of the photopolymerization initiator may include2-hydroxy-2-methyl-1-phenyl-1-propanone and 1-hydroxy-cyclohexylphenylketone, with 2-hydroxy-2-methyl-1-phenyl-1-propanone being preferred forits solubility.

A polymer obtained by polymerizing polymerizable material (2) composedsolely of compound (2) may be produced into a polymer similar to thepolymer obtained by polymerizing polymerizable material (1) composedsolely of compound (1), in accordance with the method for ring-openingcompound (2) as a precursor in the method of the present invention, i.e.hydrolytic ring-opening with acid, for example, hydrolytic ring-openingin a water-containing solvent in the presence of a catalyst.

The polymers of the present invention obtained by polymerizingpolymerizable material (1) or (2) may be formed into films or pellets byconventional processes, and these may be used as materials for coatings,optical materials, dental materials, electronic materials, printingmaterials, or the like materials.

Compounds (1) and (2) of the present invention have a hydrophilicurethane bond in the molecular structure of the (meth)acrylate compound,and compound (1) additionally has hydroxyl groups, so that thesecompounds are excellently photopolymerizable, and expected to furtherhave hydrophilicity and adhesivity. Thus these compounds and polymersthereof are expected to provide applications as raw materials or stockmaterials in a variety of fields including the medical field. Inparticular, compound (2) may also find one of its applications as aprecursor for compound (1), and the polymer obtained by polymerizationof polymerizable material (2) containing compound (2) may be producedinto a polymer similar to the polymer obtained by polymerization ofpolymerizable material (1) containing compound (1), by hydrolyticring-opening with acid.

In the method for preparing compound (1) according to the presentinvention, the reaction path is employed wherein compound (2) is used asa precursor, so that preparation of the objective compound (1) isfacilitated.

EXAMPLES

The present invention will now be explained in more detail withreference to Examples, which are illustrative only and are not intendedto limit the present invention.

Preparation Example 1 Synthesis of Compound Represented by Formula (3)

2,3-O-isopropylideneglycerol was prepared by the following synthesisprocess in accordance with the method described in M. Renoll, M. S.Newman, Org. Syn. Coll. 3, 502 (1955).

In a pear-shaped flask equipped with a calcium tube, a condenser, and aDean-Stark trap, 100 g of glycerine, 300 ml of acetone, 3 g ofp-toluenesulfonic acid monohydrate, and 300 ml of petroleum ether wereplaced, and heated to reflux in an oil bath set at 50° C.. After 12hours, when about 23 ml of water was collected and no further formationof water was confirmed, the reaction mixture was cooled to roomtemperature. 3 g of sodium acetate was added, and the mixture wasstirred for 30 minutes. Petroleum ether and acetone were distilled offin an evaporator. The resulting crude product was purified by vacuumdistillation to give 130.6 g of 2,3-O-isopropylideneglycerol in the formof colorless, transparent liquid at 91% yield. ¹H-NMR spectral data areshown below:

¹H-NMR (CDCl₃) 1.3-1.5 ppm, d, CH ₃(6H) 1.9 ppm, s, OH(1H) 3.5-4.3 ppm,m, CH ₂CHCH ₂(5H)

Preparation Example 2 Synthesis of Compound Represented by Formula (3)

The process of Preparation Example 1 was generally repeated, except thatacetone was replaced with methyl ethyl ketone, to give 139.6 g of2,3-O-sec-butylideneglycerol in the form of colorless, transparentliquid at 88% yield. ¹H-NMR spectral data are shown below:

¹H-NMR (CDCl₃) 0.8-1.0 ppm, t, CH₂CH ₃(3H) 1.2-1.4 ppm, d, CH ₃(3H)1.6-1.8 ppm, q, CH ₂CH₃(2H) 1.9 ppm, s, OH(1H) 3.5-4.3 ppm, m, CH ₂CHCH₂(5H)

Preparation Example 3 Synthesis of Compound Represented by Formula (3)

2,3-O-isopropylideneglycerine-α-monopolyethylene glycol was prepared bythe following synthesis process in accordance with the method describedin JP-6-145341-A.

13.2 g (0.1 mole) of isopropylidene glycerol and 0.2 g of potassiumhydroxide were placed in a 1 L autoclave, which was flushed withnitrogen gas and heated to 100° C.. Under the conditions of 100 to 150°C.. and 10 kg/cm² or lower, 230 g (5.22 mole) of ethylene oxide wasadded over 3 hours, and the reaction was continued for further 1 hour.The reaction system was cooled to 60° C.. while the unreacted ethyleneoxide was removed by evaporation in a stream of nitrogen. Then aceticacid was added to adjust the pH of the reaction mixture to 7.0, and thereaction mixture was heated at 100° C.. at 100 mmHg or lower for 1 hourto distill off water. The precipitated salt was filtered out to give197.3 g of 2,3-O-isopropylideneglycerine-α-monopolyethylene glycol.¹H-NMR spectral data are shown below:

¹H-NMR (CDCl₃) 1.3-1.5 ppm, d, CH ₃(6H) 1.9 ppm, s, OH(1H) 3.4-4.3 ppm,m, (CH ₂CH ₂O)₄₈, CH ₂CHCH ₂(197H)

Example 1 Synthesis of Compound (2)

In a pear-shaped flask, 6.60 g of 2,3-O-isopropylideneglycerolsynthesized in Preparation Example 1 and 1 ml of pyridine were placed,7.37 g of methacryloyloxyethyl isocyanate (manufactured by SHOWA DENKOK.K.) was measured out, and a dropping funnel and a calcium tube wereinstalled on the flask. The methacryloyloxyethyl isocyanate was addedslowly dropwise at room temperature in dark, and reacted in an oil bathset at 50° C.. for 7 hours. After the reaction was completed, pyridineand excess 2,3-O-isopropylideneglycerol were distilled off in vacuo togive 12.7 g of 2,3-O-isopropylideneglyceryl-1-methacryloyloxyethylurethane in the form of white solid at 93% yield. ¹H-NMR spectral dataare shown below:

¹H-NMR (CDCl₃) 1.3-1.5 ppm, d, CH ₃(6H) 1.9 ppm, s, CH₂═CH(CH ₃) (3H)3.4-4.4 ppm, m, OCH ₂CH ₂NH CH ₂CHCH ₂(9H) 5.1 ppm, s, NH(1H) 5.6, 6.1ppm, s, CH ₂═C(CH₃) (2H)

The resulting product was analyzed by HPLC under the followingconditions to confirm that the purity of the obtained2,3-O-isopropylideneglyceryl-1-methacryloyloxyethyl urethane was notlower than 98%.

(Conditions of HPLC)

-   Eluent: water/acetonitrile=4/6 (v/v); Column: ODS; Detector: UV (220    nm); Flow rate: 1.0 ml/min; Column oven temperature: 40° C..

Example 2 Synthesis of Compound (2)

The process of Example 1 was generally repeated, except that2,3-O-isopropylideneglycerol was replaced with2,3-O-sec-butylideneglycerol synthesized in Preparation Example 2, togive 13.8 g of 2,3-O-sec-isobutylideneglyceryl-1-methacryloyloxyethylurethane in the form of colorless, transparent liquid at 96% yield.¹H-NMR spectral data are shown below:

¹H-NMR (CDCl₃) 0.8-1.0 ppm, t, CH₂CH ₃(3H) 1.2-1.4 ppm, d, CH ₃(3H)1.6-1.8 ppm, q, CH ₂CH₃(2H) 1.9 ppm, s, CH₂═CH(CH ₃) (3H) 3.4-4.4 ppm,m, OCH ₂CH₂NH CH ₂CHCH₂(9H) 5.1 ppm, s, NH(1H) 5.6, 6.1 ppm, s, CH₂═C(CH₃)

The resulting product was analyzed by HPLC in the same way as in Example1 to confirm that the purity of the obtained2,3-O-sec-isobutylideneglyceryl-1-methacryloyloxyethyl urethane was notlower than 97%.

Example 3 Synthesis of Compound (2)

The process of Example 1 was generally repeated, except that2,3-O-isopropylideneglycerol was replaced with2,3-O-isopropylideneglycerine-α-monopolyethylene glycol synthesized inPreparation Example 3, to give 21.3 g of2,3-O-isopropylideneglycerine-α-monopolyethyleneglycol-1-methacryloyloxyethyl urethane in the form of white solid at 96%yield. ¹H-NMR spectral data are shown below:

¹H-NMR (CDCl₃) 1.3-1.5 ppm, d, CH ₃(6H) 1.9 ppm, s, CH₂═CH(CH ₃) (3H)3.4-4.5 ppm, m, OCH ₂CH₂NH(CH ₂CH₂O)₄₈ CH ₂CHCH₂(201H) 5.1 ppm, s,NH(1H) 5.6, 6.1 ppm, s, CH ₂═C(CH₃) (2H)

The resulting product was analyzed by HPLC in the same way as in Example1 to confirm that the purity of the obtained2,3-O-isopropylideneglycerine-α-monopolyethyleneglycol-1-methacryloyloxyethyl urethane was not lower than 96%.

Example 4 Synthesis and Photopolymerization Test of Compound (1)

In a vial, magnetic stirrers, 1.0 g of2,3-O-isopropylideneglyceryl-1-methacryloyloxyethyl urethane synthesizedin Example 1, 3.9 ml of methanol, and 100 μl of 4N hydrochloric acidwere placed, and reacted under stirring at room temperature for 30minutes. As a result, the mixture was turned from a suspension to aclear solution. The mixture was further reacted under stirring for 60minutes and vacuum dried, to give 852 mg ofglyceryl-1-methacryloyloxyethyl urethane in the form of colorless,viscous liquid. ¹H-NMR spectral data are shown below:

¹H-NMR (D₂O) 1.8 ppm, s, CH₂═CH(CH ₃) (3H) 3.3-4.2 ppm, m, OCH ₂CH₂NHCH₂CHCH₂(9H) 5.6, 6.0 ppm, s, CH ₂═C(CH₃) (2H)

The resulting product was analyzed by HPLC in the same way as in Example1 to confirm that the purity of the obtainedglyceryl-1-methacryloyloxyethyl urethane was not lower than 98%.

The synthesized glyceryl-1-methacryloyloxyethyl urethane was tested forphotopolymerizability by the following process.

1.0 g of glyceryl-1-methacryloyloxyethyl urethane, 1 mg of2-hydroxy-2-methylpropiophenone, and 1 ml of ion-exchanged water wereplaced in a quartz cell that was transparent on four sides, andirradiated with UV rays from a 400 W high-pressure mercury lamp in anargon atmosphere. A small amount of samples were taken at intervals, anddiluted 1000 times with ion-exchanged water. The absorbance of eachsample at 220 nm was determined with an absorptiometer to calculate thecontent of glyceryl-1-methacryloyloxyethyl urethane monomer.

The relationship between the duration of UV irradiation and the monomerconversion rate of the obtained glyceryl-1-methacryloyloxyethyl urethaneare shown in FIG. 1.

Comparative Example 1

The measurement of Example 4 was generally repeated, except thatglyceryl-1-methacryloyloxyethyl urethane was replaced withglyceryl-1-methacrylate to determine the relationship between theduration of UV irradiation and the monomer conversion rate ofglyceryl-1-methacrylate. The results are shown in FIG. 1.

From FIG. 1, it is seen that glyceryl-1-methacryloyloxyethyl urethanehas far more excellent photopolymerizability thanglyceryl-1-methacrylate.

Example 5 Synthesis of Compound (1)

The process of Example 4 was generally repeated, except that2,3-O-isopropylideneglyceryl-1-methacryloyloxyethyl urethane wasreplaced with 2,3-O-sec-butylideneglyceryl-1-methacryloyloxyethylurethane synthesized in Example 2, to give 800 mg ofglyceryl-1-methacryloyloxyethyl urethane in the form of colorless,viscous liquid. ¹H-NMR spectral data are shown below:

¹H-NMR (D₂O) 1.8 ppm, s, CH₂═CH(CH ₃) (3H) 3.3-4.2 ppm, m, OCH ₂CH₂NHCH₂CHCH₂(9H) 5.6, 6.0 ppm, s, CH ₂═C(CH₃) (2H)

The resulting product was analyzed by HPLC in the same way as in Example1 to confirm that the purity of the obtainedglyceryl-1-methacryloyloxyethyl urethane was not lower than 97%.

Example 6 Synthesis of Compound (1)

The process of Example 4 was generally repeated, except that2,3-O-isopropylideneglyceryl-1-methacryloyloxyethyl urethane wasreplaced with 2,3-O-isopropylideneglycerine-α-monopolyethyleneglycol-1-methacryloyloxyethyl urethane synthesized in Example 3, to give831 mg of glyceryl-α-monopolyethylene glycol-1-methacryloyloxyethylurethane in the form of white solid. ¹H-NMR spectral data are shownbelow:

¹H-NMR (D₂O) 1.9 ppm, s, CH₂═CH(CH ₃) (3H) 3.4-4.4 ppm, m, OCH ₂CH₂NH(CH₂CH₂O)₄₈ CH ₂CHCH₂(201H) 5.1 ppm, s, NH(1H) 5.6, 6.1 ppm, s, CH ₂═C(CH₃)(2H)

The resulting product was analyzed by HPLC in the same way as in Example1 to confirm that the purity of the obtained glyceryl-α-monopolyethyleneglycol-1-methacryloyloxyethyl urethane was not lower than 96%.

Example 7 Synthesis of Polymer from Polymerizable Material (1) byRadical Polymerization

1.0 g of glyceryl-1-methacryloyloxyethyl urethane of not lower than 98%purity as synthesized in Example 4, 5 ml of a water/methanol mixedsolvent (2/8 (v/v)), and 5 mg of azoisobutyronitrile were measured outand placed in a test tube, and bubbled with argon gas for 30 seconds.The test tube was immediately sealed, and the mixture was reacted for 24hours at 60° C.. After the 24 hours of reaction, the reaction solutionwas placed in a dialysis membrane (trade name: SPECTRA/PORE 7(manufactured by FUNAKOSHI CO., LTD.), molecular weight cut-off: 1000),and dialyzed for 12 hours against 1 L of water, which was changed everythree hours. 300 ml of the obtained solution was placed in a pear-shapedflask and lyophilized to obtain 890 mg ofpolyglyceryl-1-methacryloyloxyethyl urethane at 89% yield.

The obtained polymer was easily dissolved in water to give a colorless,viscous solution. This solution was subjected to measurement of themolecular weight by GPC under the following conditions, to confirm thatthe weight average molecular weight of the polymer was about 56000.

(Conditions of GPC)

-   Eluent: 20 mM phosphate buffer; Column: TSK gel G4000PW_(XL)+TSK gel    G2500PW_(XL); Detector: RI; Flow rate: 0.6 ml/min; Column oven    temperature: 40° C..; Reference material: polyethylene oxide

Example 8 Synthesis of Polymer from Polymerizable Material 2) by RadicalPolymerization

1.0 g of 2,3-O-isopropylideneglyceryl-1-methacryloyloxyethyl urethane ofnot lower than 98% purity as synthesized in Example 1, 5 ml of THF, and5 mg of azoisobutyronitrile were measured out and placed in a test tube,and bubbled with argon gas for 30 seconds. The test tube was immediatelysealed, and the mixture was reacted for 24 hours at 60° C.. After the 24hours of reaction, the reaction solution was cooled down to roomtemperature, mixed with 1 ml of 4 N hydrochloric acid, and stirred for 3hours. The reaction solution was placed in a dialysis membrane (tradename: SPECTRA/PORE 7 (manufactured by FUNAKOSHI CO., LTD.), molecularweight cut-off: 1000), and dialyzed for 12 hours against 1 L of water,which was changed every three hours. 300 ml of the obtained solution wasplaced in a pear-shaped flask and lyophilized to obtain 723 mg ofpolyglyceryl-1-methacryloyloxyethyl urethane at 84% yield.

The obtained polymer was easily dissolved in water to give a colorless,viscous solution. This solution was subjected to measurement of themolecular weight by GPC in the same way as in Example 7, to confirm thatthe weight average molecular weight of the polymer was about 52000.

Although the present invention has been described with reference to thepreferred examples, it should be understood that various modificationsand variations can be easily made by those skilled in the art withoutdeparting from the spirit of the invention. Accordingly, the foregoingdisclosure should be interpreted as illustrative only and is not to beinterpreted in a limiting sense. The present invention is limited onlyby the scope of the following claims.

1. A cyclic ketal (meth)acrylate compound having a urethane bondrepresented by the formula (2):

wherein R₁ stands for a hydrogen atom or a methyl group, R₂ stands for—(CH₂)n-, and R₃ stands for —(CH₂)m-, provided that n is an integer of 1to 4 and m is an integer of 1 to 8; (AO) stands for an oxyalkylene grouphaving 2 to 4 carbon atoms, x is an integer of 0 to 1000, R₄ and R₅ mayeither be the same or different, and each stands for a hydrogen atom, amethyl group, or an ethyl group.